The present invention is directed toward an overhead garage door assembly and more particularly to an improved safety device therefor which is adapted to retain broken portions of a counterbalance coil spring in the event of breakage of the spring.
Counterbalance coil springs have been used for many years in most overhead garage door structures for assisting the operator in the opening and closing of the door. Such springs are utilized even when motorized automatic garage door openers are utilized since the garage doors are relatively heavy and the springs provide the needed assistance to raise the doors and to prevent the doors from closing too quickly and out of control.
The counterbalance springs which are normally used are tension springs which, when stretched the required amount, are placed under very considerable tension. It is known that after a period of time and use, the spring metal may rupture due to wear. Such rupture inevitably occurs when the spring is at virtually full tension. As a result, upon breakage, the tension is released and broken pieces of spring may be flung about with considerable force which may cause injury to property or people in the vicinity.
Proposals have been made in the past to reduce the likelihood of any such injury by providing a flexible cable or the like which passes entirely through each coil spring and is secured to a structural member at each end and preferably beyond the end of each spring. Examples of such devices are shown in U.S. Pat. Nos. 3,958,367 to Fairman and 4,082,133 to Halopoff. In theory, if there is a breakage of the spring when utilizing either the Fairman or Halopoff devices, the elongated member passing through the spring will retain the broken pieces of the spring. It has been found, however, that breakage most frequently occurs at the very end of the spring where it is normally bent into a hook so that it can be secured to a support. Since the elongated member of the prior art devices does not pass through this portion of the spring, it will not retain the same in the event of a breakage and damage or injury can still occur.